THE UK has spent hundreds of millions of pounds subsidising the burning of woody biomass that releases more emissions than coal, research has found.

Using wood – much of it imported from America – for biomass power and heat is often seen as a relatively cheap and flexible way of supplying renewable energy, but a report by Chatham House suggests the process could be more harmful than traditional energy sources.

Duncan Brack, author of the report, wrote that “while some instances of biomass energy use may result in lower life-cycle emissions than fossil fuels”, this was not the case in “most circumstances”.

“Comparing technologies of similar ages, the use of woody biomass for energy will release higher levels of emissions than coal and considerably higher levels than gas.”

The report said: “It is not valid to claim that because trees absorb carbon as they grow, the emissions from burning them can be ignored.”

Mr Brack, who was a special adviser to former energy and climate change secretary Chris Huhne, is an associate fellow at the international affairs think tank.

Mr Huhne is now the Europe chairman of Zilkha Biomass Energy, which produces water-resistant biomass pellets which are transportable like coal.

A spokesman for the Department for Business, Energy and Industrial Strategy said: “All biomass power plants in the UK have to meet mandatory sustainability criteria to ensure they reduce carbon emissions.

“Biomass conversion projects are a useful way to convert old polluting coal power stations into lower carbon electricity sources, whilst keeping down bills.”